Tutorial by Examples: java

A common use case for extension methods is to improve an existing API. Here are examples of adding exist, notExists and deleteRecursively to the Java 7+ Path class: fun Path.exists(): Boolean = Files.exists(this) fun Path.notExists(): Boolean = !this.exists() fun Path.deleteRecursively(): Bool...

With this declaration: fun Temporal.toIsoString(): String = DateTimeFormatter.ISO_INSTANT.format(this) You can now simply: val dateAsString = someInstant.toIsoString()

The publisher-subscriber is a familiar concept given the rise of YouTube, Facebook and other social media services. The basic concept is that there is a Publisher who generates content and a Subscriber who consumes content. Whenever the Publisher generates content, each Subscriber is notified. Subsc...

To use Leaflet, load its stylesheet and JavaScript file to your page: <link rel="stylesheet" href="/css/leaflet.css" /> <script src="/js/leaflet.js"></script> These resources can be downloaded from a variety of locations such as Leaflet's homepage...

public static class ThreadLocalExample { private static final ThreadLocal<SimpleDateFormat> format = ThreadLocal.withInitial(() -> new SimpleDateFormat("yyyyMMdd_HHmm")); public String formatDate(Date date) { return format.get().format(date); ...

Required modules npm install --save-dev webpack extract-text-webpack-plugin file-loader css-loader style-loader Folder structure . └── assets    ├── css     ├── images    └── js webpack.config.js const webpack = require('webpack'); const ExtractTextPlugin = require('extract-text-webp...

A java.util.Date object does not have a concept of time zone. There is no way to set a timezone for a Date There is no way to change the timezone of a Date object A Date object created with the new Date() default constructor will be initialised with the current time in the system default timezo...

These examples assume that you already know what Java 7's NIO is in general, and you are used to writing code using java.io.File. Use these examples as a means to quickly find more NIO-centric documentation for migrating. There is much more to Java 7's NIO such as memory-mapped files or opening a Z...

Prerequisite: Installing Gradle Once you have Gradle installed, you can setup a new or existing project by running cd $PROJECT_DIR gradle init --type=java-library Note that there are other project types like Scala you can get started with, but we'll use Java for this example. You will end up ...

If you want to see the generated bytecode for a Java program, you can use the provided javap command to view it. Assuming that we have the following Java source file: package com.stackoverflow.documentation; import org.springframework.stereotype.Service; import java.io.IOException; import j...

To obtain a Java's Class object from Kotlin's KClass use the .java extension property: val stringKClass: KClass<String> = String::class val c1: Class<String> = stringKClass.java val c2: Class<MyClass> = MyClass::class.java The latter example will be optimized by the compile...

When you need to pass a collection into a Java method: import scala.collection.JavaConverters._ val scalaList = List(1, 2, 3) JavaLibrary.process(scalaList.asJava) If the Java code returns a Java collection, you can turn it into a Scala collection in a similar manner: import scala.collectio...

First need to create a final static logger object: final static Logger logger = Logger.getLogger(classname.class); Then, call logging methods: //logs an error message logger.info("Information about some param: " + parameter); // Note that this line could throw a NullPointerException!...

String hubUrl = "http://localhost:4444/wd/hub" DesiredCapabilities capability = DesiredCapabilities.firefox(); //or which browser you want RemoteWebDriver driver = new RemoteWebDriver(hubUrl, capability);

JSON stands for "JavaScript Object Notation", but it's not JavaScript. Think of it as just a data serialization format that happens to be directly usable as a JavaScript literal. However, it is not advisable to directly run (i.e. through eval()) JSON that is fetched from an external source...

To connect using java.sql.DriverManager you need a JDBC url to connect to your database. JDBC urls are database specific, but they are all of the form jdbc:<subprotocol>:<subname> Where <subprotocol> identifies the driver or database (for example postgresql, mysql, firebirdsql,...

wikipedia definition: Command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an action or trigger an event at a later time UML diagram from dofactory: Basic components and workflow: Command declares an interface for abst...

Groovy has access to all java classes, in fact Groovy classes ARE Java classes and can be run by the JVM directly. If you are working on a Java project, using Groovy as a simple scripting language to interact with your java code is a no-brainer. To make things even better, nearly any Java class ca...

In order to have google maps work properly with turbolinks, add the javascript tag directly to the layout header rather than including it in a view. # app/views/layouts/my_layout.html.haml !!! %html{:lang => 'en'} %head - # ... = google_maps_api_script_tag The google_maps_api_s...

Suppose, there is a .google_map div, which will become the map, and which has the address fields to show as markers as data attribute. For example: <!-- http://localhost:3000/profiles/123 --> <div class="google_map" data-address-fields="[ {label: 'Work address', value: ...